/* ─────────────────────────────────────────────────────────────
   Aviation Field Manual, reissued.
   遙控無人機題庫測驗 — design system
   See .impeccable.md for principles.
   ───────────────────────────────────────────────────────────── */

:root {
  /* Color — paper & ink, OKLCH for perceptual uniformity */
  --paper:        oklch(97.5% 0.022 87);   /* #fdf6e7  page */
  --paper-warm:   oklch(98.5% 0.018 87);   /* #fffaef  cards */
  --paper-deep:   oklch(94%   0.038 90);   /* #fbecbe  selected highlight */
  --rule:         oklch(89%   0.034 86);   /* #ecdcb4  borders */
  --rule-strong:  oklch(78%   0.085 80);   /* #d4a94a  emphasis borders */
  --ink:          oklch(33%   0.038 70);   /* #5a4218  body */
  --ink-soft:     oklch(40%   0.034 70);   /* #6b5028  secondary */
  --ink-faint:    oklch(58%   0.060 78);   /* #9c7a3a  labels */
  --brass:        oklch(63%   0.090 85);   /* #b08a3a  primary */
  --brass-deep:   oklch(56%   0.090 85);   /* #9a7530  hover */
  --on-brass:     oklch(98.5% 0.018 87);

  /* Diagnostic — pass / fail / mark, all dust-tinted */
  --pass-bg:      oklch(95% 0.045 130);
  --pass-rule:    oklch(72% 0.110 130);
  --pass-ink:     oklch(43% 0.090 130);
  --fail-bg:      oklch(93% 0.055 50);
  --fail-rule:    oklch(78% 0.120 50);
  --fail-ink:     oklch(45% 0.130 40);
  --mark-bg:      oklch(96% 0.060 80);
  --mark-rule:    oklch(72% 0.135 80);

  /* Shadow — almost imperceptible, like ink soaked into paper */
  --shadow-1: 0 1px 0 oklch(85% 0.04 80 / .3), 0 0 0 1px oklch(85% 0.04 80 / .15);
  --shadow-2: 0 2px 12px oklch(45% 0.04 70 / .08);

  /* Typography */
  --font-display: "Source Serif 4", "Noto Serif TC", Georgia, "Times New Roman", serif;
  --font-body:    "Noto Serif TC", "Source Serif 4", "PingFang TC", "Songti TC", serif;
  --font-mono:    "Sometype Mono", ui-monospace, "SF Mono", Menlo, monospace;

  /* Type scale — 5 steps, 1.25 ratio, fluid for headings */
  --t-xs:   12px;
  --t-sm:   13px;
  --t-base: 15px;
  --t-md:   17px;
  --t-lg:   clamp(19px, 1.05rem + 0.4vw, 22px);
  --t-xl:   clamp(24px, 1.2rem + 1.2vw, 32px);
  --t-2xl:  clamp(34px, 1.6rem + 2vw, 52px);
  --t-3xl:  clamp(48px, 2rem + 3.5vw, 80px);

  /* Spacing — 4pt scale */
  --s-1:  4px;
  --s-2:  8px;
  --s-3:  12px;
  --s-4:  16px;
  --s-5:  24px;
  --s-6:  32px;
  --s-7:  48px;
  --s-8:  64px;
  --s-9:  96px;

  --radius:    4px;
  --radius-lg: 6px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: var(--t-base);
  line-height: 1.65;
  font-feature-settings: "ss01", "ss02", "kern", "liga";
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

#app {
  max-width: 980px;
  margin: 0 auto;
  padding: var(--s-7) var(--s-4) var(--s-8);
}

/* ── Typography defaults ───────────────────────────────────── */
h1, h2, h3, h4 {
  font-family: var(--font-display);
  color: var(--ink);
  font-weight: 600;
  letter-spacing: -0.005em;
  line-height: 1.15;
  margin: 0;
}
h1 { font-size: var(--t-2xl); font-weight: 600; }
h2 { font-size: var(--t-xl); }
h3 { font-size: var(--t-lg); }

p { margin: 0; }

/* Numerals always tabular & monospace where we want alignment */
.num,
.tabular {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum";
}

/* Manual-style label: small caps, kerned, the spine of the brand */
.label {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

.subtitle {
  color: var(--ink-soft);
  font-size: var(--t-sm);
}

/* ── Atoms ─────────────────────────────────────────────────── */
.button {
  font: inherit;
  font-size: var(--t-sm);
  font-weight: 500;
  letter-spacing: 0.02em;
  padding: var(--s-2) var(--s-4);
  border-radius: var(--radius);
  border: 1px solid var(--rule);
  background: var(--paper-warm);
  color: var(--ink);
  cursor: pointer;
  transition: border-color 160ms ease, background 160ms ease, color 160ms ease;
}
.button:hover { border-color: var(--rule-strong); background: var(--paper); }
.button[data-primary] {
  background: var(--brass);
  border-color: var(--brass-deep);
  color: var(--on-brass);
  font-weight: 500;
}
.button[data-primary]:hover { background: var(--brass-deep); }
.button:disabled { opacity: .4; cursor: not-allowed; }
.button:focus-visible { outline: 2px solid var(--brass); outline-offset: 2px; }

.loading { color: var(--ink-faint); text-align: center; padding: var(--s-7) 0; font-style: italic; }
.error {
  background: var(--fail-bg);
  border: 1px solid var(--fail-rule);
  color: var(--fail-ink);
  padding: var(--s-3) var(--s-4);
  border-radius: var(--radius);
  font-size: var(--t-sm);
}

/* ─────────────────────────────────────────────────────────────
   HOME — Field Manual cover & contents
   ───────────────────────────────────────────────────────────── */
.home-hero {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: var(--s-4);
  align-items: end;
  padding-bottom: var(--s-5);
  margin-bottom: var(--s-7);
  border-bottom: 1px solid var(--rule);
}
.home-hero .hero-mark {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--brass-deep);
  border: 1px solid var(--brass-deep);
  padding: 2px var(--s-2);
  border-radius: 2px;
  text-transform: uppercase;
  align-self: end;
}
.home-hero h1 {
  font-size: var(--t-3xl);
  font-weight: 600;
  letter-spacing: -0.02em;
  font-family: var(--font-display);
}
.home-hero .hero-meta {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--ink-faint);
  text-align: right;
  align-self: end;
  text-transform: uppercase;
}
.home-hero .hero-sub {
  grid-column: 1 / -1;
  color: var(--ink-soft);
  font-size: var(--t-md);
  max-width: 60ch;
  margin-top: var(--s-3);
}

.contents-label {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: var(--s-3);
}
.contents-label .num { font-size: 11px; letter-spacing: 0.2em; color: var(--ink-faint); }

.bank-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
}
.bank-card {
  display: grid;
  grid-template-columns: 56px 1fr auto;
  gap: var(--s-4);
  align-items: baseline;
  padding: var(--s-5) var(--s-4);
  border-top: 1px solid var(--rule);
  cursor: pointer;
  transition: background 160ms ease, padding-left 220ms ease;
  background: transparent;
}
.bank-list .bank-card:last-child { border-bottom: 1px solid var(--rule); }
.bank-card:hover, .bank-card:focus { outline: none; background: var(--paper-warm); padding-left: var(--s-5); }
.bank-card:focus-visible { background: var(--paper-warm); outline: 1px solid var(--brass); outline-offset: -1px; }

.bank-card .bank-num {
  font-family: var(--font-mono);
  font-size: 22px;
  color: var(--brass);
  font-weight: 500;
  font-variant-numeric: tabular-nums;
  align-self: start;
}
.bank-card .bank-body { display: flex; flex-direction: column; gap: var(--s-2); }
.bank-card .bank-title {
  font-family: var(--font-display);
  font-size: var(--t-lg);
  font-weight: 600;
  color: var(--ink);
  letter-spacing: -0.005em;
}
.bank-card .bank-meta {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--ink-faint);
  text-transform: uppercase;
}
.chapter-pills {
  list-style: none;
  padding: 0;
  margin: var(--s-1) 0 0;
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-1) var(--s-4);
  font-size: var(--t-xs);
  color: var(--ink-soft);
}
.chapter-pills li {
  display: inline-flex;
  align-items: baseline;
  gap: var(--s-1);
}
.chapter-pills li::before {
  content: "§";
  color: var(--ink-faint);
  font-family: var(--font-display);
  margin-right: 2px;
}
.chapter-pills .pill-count {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  color: var(--ink-faint);
}

.bank-card .bank-cta {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.12em;
  color: var(--ink-soft);
  padding: 6px 12px;
  border: 1px solid var(--rule);
  border-radius: 2px;
  white-space: nowrap;
  align-self: center;
  transition: color 220ms ease, border-color 220ms ease, background 220ms ease, transform 220ms ease;
}
.bank-card:hover .bank-cta,
.bank-card:focus .bank-cta {
  color: var(--on-brass);
  border-color: var(--brass-deep);
  background: var(--brass);
  transform: translateX(2px);
}

/* ─────────────────────────────────────────────────────────────
   SETUP — exam configuration sheet
   ───────────────────────────────────────────────────────────── */
.setup-hero {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: var(--s-4);
  align-items: baseline;
  padding-bottom: var(--s-4);
  margin-bottom: var(--s-5);
  border-bottom: 1px solid var(--rule);
}
.back-link {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--ink-faint);
  text-decoration: none;
  text-transform: uppercase;
  border-bottom: 1px solid transparent;
  transition: color 160ms ease, border-color 160ms ease;
}
.back-link:hover { color: var(--brass); border-color: var(--brass); }
.setup-hero h1 {
  grid-column: 1 / -1;
  font-size: var(--t-2xl);
  font-weight: 600;
}
.setup-hero .subtitle {
  grid-column: 1 / -1;
  font-family: var(--font-display);
  font-size: var(--t-md);
  font-style: italic;
  color: var(--ink-soft);
  max-width: 60ch;
}

.setup-form {
  display: grid;
  gap: var(--s-6);
}
.setup-form fieldset {
  border: 0;
  padding: 0;
  margin: 0;
  display: grid;
  gap: var(--s-3);
}
.setup-form legend {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--ink-faint);
  text-transform: uppercase;
  padding: 0;
  margin-bottom: var(--s-3);
  border-bottom: 1px solid var(--rule);
  padding-bottom: var(--s-2);
  width: 100%;
}

/* Chapter checkbox rows look like a manual table-of-contents */
.ck-row {
  display: grid;
  grid-template-columns: 32px auto 1fr auto;
  gap: var(--s-3);
  align-items: baseline;
  padding: var(--s-2) 0;
  border-bottom: 1px dashed var(--rule);
  cursor: pointer;
  font-size: var(--t-base);
  color: var(--ink);
}
.ck-row:last-child { border-bottom: 0; }
.ck-row input[type="checkbox"] {
  appearance: none;
  width: 16px; height: 16px;
  border: 1px solid var(--ink-faint);
  border-radius: 2px;
  background: var(--paper-warm);
  cursor: pointer;
  position: relative;
  align-self: center;
  margin: 0;
  grid-column: 1;
  justify-self: end;
}
.ck-row input[type="checkbox"]:checked {
  background: var(--brass);
  border-color: var(--brass-deep);
}
.ck-row input[type="checkbox"]:checked::after {
  content: "";
  position: absolute;
  inset: 3px;
  border: solid var(--on-brass);
  border-width: 0 2px 2px 0;
  transform: rotate(43deg) translate(-1px, -1px);
  width: 4px; height: 8px;
  border-radius: 0;
  left: 4px;
  top: 1px;
}
.ck-row .ck-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--t-sm);
  color: var(--ink-faint);
}
.ck-row .ck-count {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--t-xs);
  color: var(--ink-faint);
  letter-spacing: 0.04em;
}

.setup-row {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: var(--s-4) var(--s-5);
  align-items: baseline;
  padding: var(--s-3) 0;
  border-bottom: 1px dashed var(--rule);
}
.setup-row:last-child { border-bottom: 0; }
.setup-row .setup-key {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--ink-faint);
  text-transform: uppercase;
  padding-top: 6px;
}
.setup-row .setup-control {
  display: flex;
  align-items: baseline;
  gap: var(--s-3);
  flex-wrap: wrap;
}
.setup-form input[type="number"] {
  font: inherit;
  font-family: var(--font-mono);
  font-size: var(--t-md);
  padding: 6px 10px;
  border: 0;
  border-bottom: 1px solid var(--ink-faint);
  background: transparent;
  width: 6ch;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
  text-align: right;
  border-radius: 0;
}
.setup-form input[type="number"]:focus {
  outline: 0;
  border-bottom-color: var(--brass);
  background: var(--paper-deep);
}

/* Switch — beautified toggle for time-limit etc. */
.setup-form .switch {
  display: inline-flex;
  align-items: center;
  gap: var(--s-2);
  cursor: pointer;
  user-select: none;
  margin-left: var(--s-2);
}
.setup-form .switch input { display: none; }
.setup-form .switch-track {
  position: relative;
  width: 38px;
  height: 20px;
  border-radius: 999px;
  border: 1px solid var(--rule-strong);
  background: var(--paper-warm);
  transition: background 200ms ease, border-color 200ms ease;
  flex-shrink: 0;
}
.setup-form .switch-thumb {
  position: absolute;
  top: 2px; left: 2px;
  width: 14px; height: 14px;
  border-radius: 50%;
  background: var(--paper);
  border: 1px solid var(--rule-strong);
  box-shadow: 0 1px 1px oklch(45% 0.04 70 / .15);
  transition: left 200ms cubic-bezier(.55, 0, .15, 1.4), background 200ms ease, border-color 200ms ease;
}
.setup-form .switch input:checked ~ .switch-track {
  background: var(--brass);
  border-color: var(--brass-deep);
}
.setup-form .switch input:checked ~ .switch-track .switch-thumb {
  left: 20px;
  background: var(--paper-warm);
  border-color: var(--brass-deep);
}
.setup-form .switch input:focus-visible ~ .switch-track {
  outline: 2px solid var(--brass);
  outline-offset: 2px;
}
.setup-form .switch-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--ink-faint);
  text-transform: uppercase;
  transition: color 200ms ease;
  font-feature-settings: "tnum";
}
.setup-form .switch input:checked ~ .switch-label {
  color: var(--brass-deep);
  font-weight: 600;
}
/* When disabled, dim the minutes input visually */
.setup-form input[type="number"]:disabled {
  color: var(--ink-faint);
  border-bottom: 1px dashed var(--rule);
  opacity: 0.45;
  cursor: not-allowed;
}
.setup-form input[type="number"]:disabled + .hint,
.setup-form input[type="number"]:disabled ~ .hint {
  opacity: 0.45;
}

.hint {
  font-family: var(--font-mono);
  font-size: var(--t-xs);
  color: var(--ink-faint);
  letter-spacing: 0.06em;
}
.hint .hint-em { color: var(--brass-deep); font-weight: 500; }

.actions {
  display: flex;
  justify-content: flex-end;
  gap: var(--s-3);
  margin-top: var(--s-5);
  padding-top: var(--s-4);
  border-top: 1px solid var(--rule);
}

/* ─────────────────────────────────────────────────────────────
   EXAM — manual page with marginalia
   ───────────────────────────────────────────────────────────── */
.exam-topbar {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: var(--s-4);
  align-items: center;
  padding: var(--s-3) 0;
  margin-bottom: var(--s-5);
  border-bottom: 1px solid var(--rule);
  position: sticky;
  top: 0;
  background: var(--paper);
  z-index: 5;
}
.exam-topbar .ex-meta { display: flex; flex-direction: column; gap: 2px; }
.exam-topbar .ex-bank {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--ink-faint);
  text-transform: uppercase;
}
.exam-topbar .ex-progress {
  font-family: var(--font-display);
  font-size: var(--t-md);
  font-weight: 600;
  color: var(--ink);
}
.exam-topbar .ex-progress .num { font-family: var(--font-mono); font-weight: 500; }
.topbar-right { display: flex; gap: var(--s-3); align-items: center; }

.exam-timer {
  font-family: var(--font-mono);
  font-size: var(--t-md);
  font-weight: 500;
  font-variant-numeric: tabular-nums;
  color: var(--ink);
  padding: var(--s-1) var(--s-3);
  border: 1px solid var(--rule);
  background: var(--paper-warm);
  border-radius: var(--radius);
  letter-spacing: 0.04em;
}
.exam-timer.is-low {
  color: var(--fail-ink);
  border-color: var(--fail-rule);
  background: var(--fail-bg);
}
.exam-timer::before {
  content: "倒數 ";
  font-family: var(--font-body);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--ink-faint);
  margin-right: 4px;
  font-weight: 400;
}

.exam-main {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--s-5);
}
@media (min-width: 880px) {
  .exam-main { grid-template-columns: minmax(0, 1fr) 200px; gap: var(--s-7); }
}

.exam-q {
  background: transparent;
  border: 0;
  padding: 0;
}
.chapter-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--ink-faint);
  text-transform: uppercase;
  padding-bottom: var(--s-2);
  border-bottom: 1px solid var(--rule);
  margin-bottom: var(--s-4);
  display: flex;
  justify-content: space-between;
}
.chapter-label .ch-section::before { content: "§ "; color: var(--ink-faint); }

.exam-q-text {
  font-family: var(--font-display);
  color: var(--ink);
  font-size: var(--t-lg);
  line-height: 1.55;
  margin: 0 0 var(--s-5);
  max-width: 38em;
}

.exam-choices {
  display: flex;
  flex-direction: column;
  gap: 0;
  margin-bottom: var(--s-5);
  border-top: 1px solid var(--rule);
}
.exam-choice {
  display: grid;
  grid-template-columns: 24px auto 1fr;
  gap: var(--s-3);
  cursor: pointer;
  padding: var(--s-3) var(--s-1);
  border-bottom: 1px solid var(--rule);
  align-items: baseline;
  transition: background 140ms ease;
  font-size: var(--t-base);
  line-height: 1.55;
  color: var(--ink-soft);
}
.exam-choice:hover { background: var(--paper-warm); }
.exam-choice input { display: none; }
.exam-choice .exam-choice-letter {
  font-family: var(--font-mono);
  font-weight: 500;
  font-size: var(--t-sm);
  color: var(--ink-faint);
  letter-spacing: 0.06em;
  align-self: baseline;
  text-align: center;
  min-width: 14px;
}
.exam-choice .exam-choice-bullet {
  width: 12px;
  height: 12px;
  border: 1px solid var(--ink-faint);
  border-radius: 50%;
  align-self: center;
}
.exam-choice .exam-choice-text { color: var(--ink); }
.exam-choice.is-selected { background: var(--paper-deep); }
.exam-choice.is-selected .exam-choice-letter { color: var(--brass-deep); font-weight: 600; }
.exam-choice.is-selected .exam-choice-bullet {
  border-color: var(--brass-deep);
  background: radial-gradient(circle, var(--brass-deep) 35%, transparent 38%);
}
.exam-choice.is-selected .exam-choice-text { color: var(--ink); font-weight: 500; }

.exam-q-foot {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: var(--s-3);
  align-items: center;
}
.mark-toggle {
  display: inline-flex;
  align-items: center;
  gap: var(--s-2);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--ink-soft);
  text-transform: uppercase;
  cursor: pointer;
  justify-self: center;
}
.mark-toggle input[type="checkbox"] {
  appearance: none;
  width: 14px; height: 14px;
  border: 1px solid var(--ink-faint);
  border-radius: 2px;
  position: relative;
  cursor: pointer;
}
.mark-toggle input[type="checkbox"]:checked {
  background: var(--mark-bg);
  border-color: var(--rule-strong);
}
.mark-toggle input[type="checkbox"]:checked::after {
  content: "★";
  position: absolute;
  font-size: 10px;
  color: var(--brass-deep);
  line-height: 1;
  top: 1px; left: 2px;
}

/* TOC marginalia — like a manual's side index */
.exam-toc {
  border-left: 0;
  padding-left: 0;
}
@media (min-width: 880px) {
  .exam-toc {
    padding-left: var(--s-4);
    border-left: 1px solid var(--rule);
    align-self: start;
    position: sticky;
    top: 80px;
  }
}
.exam-toc .toc-head {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--ink-faint);
  text-transform: uppercase;
  margin-bottom: var(--s-3);
}
.toc-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 1px;
  background: var(--rule);
  border: 1px solid var(--rule);
  margin-bottom: var(--s-4);
}
.toc-cell {
  font: inherit;
  font-family: var(--font-mono);
  font-size: var(--t-xs);
  font-variant-numeric: tabular-nums;
  aspect-ratio: 1;
  border: 0;
  background: var(--paper-warm);
  color: var(--ink-faint);
  cursor: pointer;
  padding: 0;
  transition: background 140ms ease, color 140ms ease;
}
.toc-cell:hover { background: var(--paper-deep); color: var(--ink); }
.toc-cell.is-answered {
  background: var(--brass);
  color: var(--on-brass);
  font-weight: 500;
}
.toc-cell.is-marked {
  box-shadow: inset 0 0 0 2px var(--rule-strong);
}
.toc-cell.is-current {
  background: var(--ink);
  color: var(--paper-warm);
  font-weight: 600;
}

.toc-legend {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: var(--s-2);
}
.toc-legend li {
  display: grid;
  grid-template-columns: 12px 1fr auto;
  gap: var(--s-2);
  align-items: center;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--ink-soft);
  text-transform: uppercase;
}
.toc-legend .toc-swatch {
  width: 10px;
  height: 10px;
  border: 1px solid var(--rule);
  background: var(--paper-warm);
  display: block;
}
.toc-legend .toc-swatch.is-answered { background: var(--brass); border-color: var(--brass-deep); }
.toc-legend .toc-swatch.is-marked { box-shadow: inset 0 0 0 2px var(--rule-strong); }
.toc-legend .toc-num {
  font-variant-numeric: tabular-nums;
  color: var(--ink-faint);
  text-align: right;
}

.mobile-only { display: none; }
@media (max-width: 879px) {
  .mobile-only { display: inline-flex; }
  .exam-toc {
    display: none;
    background: var(--paper);
    padding: var(--s-4);
    border: 1px solid var(--rule);
    margin-bottom: var(--s-5);
  }
  .exam-toc.is-open { display: block; }
}

/* ─────────────────────────────────────────────────────────────
   RESULT — examination report
   ───────────────────────────────────────────────────────────── */
.result-hero {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: var(--s-5);
  padding: var(--s-5) 0 var(--s-4);
  margin-bottom: var(--s-6);
  border-top: 2px solid var(--ink);
  border-bottom: 1px solid var(--rule);
  align-items: end;
}
.result-hero .result-bank {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--ink-faint);
  text-transform: uppercase;
  margin-bottom: var(--s-3);
  display: flex;
  justify-content: space-between;
}
.result-hero .result-stamp {
  border: 1px solid var(--rule-strong);
  padding: 2px var(--s-2);
  letter-spacing: 0.16em;
  color: var(--brass-deep);
}
.result-hero .result-score {
  font-family: var(--font-display);
  font-size: var(--t-3xl);
  font-weight: 600;
  color: var(--ink);
  line-height: 1;
  letter-spacing: -0.03em;
  display: flex;
  align-items: baseline;
  gap: var(--s-3);
}
.result-hero .result-score .score-num {
  font-family: var(--font-mono);
  font-weight: 500;
  font-variant-numeric: tabular-nums;
}
.result-hero .result-score .score-den {
  font-family: var(--font-display);
  font-size: var(--t-lg);
  color: var(--ink-faint);
  font-weight: 400;
}
.result-hero .badge {
  font-family: var(--font-mono);
  font-size: var(--t-sm);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  padding: var(--s-1) var(--s-3);
  border: 1px solid;
  border-radius: 2px;
  align-self: center;
}
.result-hero.is-pass .badge { background: var(--pass-bg); border-color: var(--pass-rule); color: var(--pass-ink); }
.result-hero.is-fail .badge { background: var(--fail-bg); border-color: var(--fail-rule); color: var(--fail-ink); }
.result-hero .result-stats {
  font-family: var(--font-mono);
  font-size: var(--t-xs);
  color: var(--ink-soft);
  letter-spacing: 0.06em;
  margin-top: var(--s-3);
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-1) var(--s-4);
}
.result-hero .result-stats span { display: inline-flex; gap: var(--s-1); }
.result-hero .result-stats .stat-label { color: var(--ink-faint); text-transform: uppercase; }
.result-hero .result-stats .stat-val {
  font-variant-numeric: tabular-nums;
  color: var(--ink);
  font-weight: 500;
}
.result-actions { display: flex; flex-direction: column; gap: var(--s-2); align-items: end; }
@media (max-width: 640px) {
  .result-hero { grid-template-columns: 1fr; }
  .result-actions { flex-direction: row; align-self: stretch; }
}

.result-filters {
  display: flex;
  gap: 0;
  margin: 0 0 var(--s-5);
  border-bottom: 1px solid var(--rule);
}
.filter-btn {
  font: inherit;
  font-family: var(--font-mono);
  padding: var(--s-2) var(--s-4);
  border: 0;
  background: transparent;
  color: var(--ink-faint);
  cursor: pointer;
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  border-bottom: 1px solid transparent;
  margin-bottom: -1px;
  transition: color 140ms, border-color 140ms;
}
.filter-btn:hover { color: var(--ink); }
.filter-btn.is-on {
  color: var(--ink);
  border-bottom-color: var(--ink);
  font-weight: 600;
}
.filter-btn .filter-num {
  font-variant-numeric: tabular-nums;
  font-weight: 400;
  color: var(--ink-faint);
  margin-left: 4px;
}
.filter-btn.is-on .filter-num { color: var(--ink-soft); }

.result-list { list-style: none; padding: 0; margin: 0; display: flex; flex-direction: column; gap: 0; }
.result-item {
  padding: var(--s-5) 0;
  border-bottom: 1px solid var(--rule);
}
.result-item:first-child { padding-top: 0; }

.result-q-head {
  display: grid;
  grid-template-columns: 56px auto 1fr;
  gap: var(--s-3);
  align-items: baseline;
  margin-bottom: var(--s-2);
}
.result-num {
  font-family: var(--font-mono);
  font-size: var(--t-md);
  font-weight: 500;
  color: var(--ink-faint);
  font-variant-numeric: tabular-nums;
}
.result-status {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-soft);
  display: inline-flex;
  align-items: baseline;
  gap: var(--s-1);
}
.result-status.is-correct { color: var(--pass-ink); }
.result-status.is-wrong { color: var(--fail-ink); }
.result-status.is-blank { color: var(--ink-faint); font-style: italic; }
.result-status .status-mark { font-weight: 700; }
.result-mark {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--brass-deep);
  letter-spacing: 0.06em;
  margin-left: var(--s-2);
}
.result-q-head .label {
  justify-self: end;
}
.result-q-text {
  font-family: var(--font-display);
  font-size: var(--t-md);
  color: var(--ink);
  margin: 0 0 var(--s-3);
  padding-left: 56px;
  line-height: 1.6;
  max-width: 50em;
}
.result-choices {
  list-style: none;
  padding: 0 0 0 56px;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: var(--s-1);
}
.result-choices li {
  font-size: var(--t-sm);
  padding: 4px var(--s-2);
  color: var(--ink-soft);
  display: grid;
  grid-template-columns: 16px 1fr auto;
  gap: var(--s-2);
  align-items: baseline;
  font-family: var(--font-display);
  border-bottom: 1px dashed transparent;
}
.result-choices li b {
  font-family: var(--font-mono);
  font-size: var(--t-xs);
  color: var(--ink-faint);
  font-weight: 500;
  letter-spacing: 0.04em;
}
.result-choices li .choice-tag {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-faint);
}
.result-choices li.is-answer {
  background: var(--pass-bg);
  color: var(--pass-ink);
}
.result-choices li.is-answer b { color: var(--pass-ink); }
.result-choices li.is-answer .choice-tag { color: var(--pass-ink); font-weight: 500; }
.result-choices li.is-mywrong {
  background: var(--fail-bg);
  color: var(--fail-ink);
  text-decoration: line-through;
  text-decoration-color: oklch(45% 0.13 40 / .35);
}
.result-choices li.is-mywrong b { color: var(--fail-ink); }
.result-choices li.is-mywrong .choice-tag { color: var(--fail-ink); font-weight: 500; }
.empty {
  font-family: var(--font-display);
  font-style: italic;
  color: var(--ink-faint);
  padding: var(--s-7);
  text-align: center;
}

/* ─────────────────────────────────────────────────────────────
   REVIEW — question bank viewer
   ───────────────────────────────────────────────────────────── */
.bank-card .bank-actions {
  display: flex;
  flex-direction: column;
  gap: var(--s-2);
  align-self: center;
  align-items: stretch;
}
.bank-card .bank-review {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.14em;
  color: var(--ink-faint);
  text-transform: uppercase;
  text-decoration: none;
  text-align: center;
  padding: 5px 12px;
  border: 1px dashed var(--rule);
  border-radius: 2px;
  white-space: nowrap;
  transition: color 160ms ease, border-color 160ms ease, background 160ms ease;
}
.bank-card .bank-review:hover,
.bank-card .bank-review:focus {
  color: var(--brass-deep);
  border-color: var(--brass);
  background: var(--paper);
  outline: none;
}

.review-hero {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: var(--s-4);
  align-items: baseline;
  padding-bottom: var(--s-4);
  margin-bottom: var(--s-5);
  border-bottom: 1px solid var(--rule);
}
.review-hero .label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--ink-faint);
  text-transform: uppercase;
  justify-self: end;
}
.review-hero h1 {
  grid-column: 1 / -1;
  font-size: var(--t-2xl);
  font-weight: 600;
}
.review-hero .subtitle {
  grid-column: 1 / -1;
  font-family: var(--font-display);
  font-size: var(--t-md);
  font-style: italic;
  color: var(--ink-soft);
  max-width: 60ch;
}

.review-filters { flex-wrap: wrap; }

.result-status.is-review {
  color: var(--ink-faint);
  font-style: normal;
}
.result-status.is-review .status-mark {
  font-family: var(--font-display);
  font-weight: 600;
  color: var(--brass);
}

.review-list .result-item:last-child { border-bottom: 1px solid var(--rule); }

@media (max-width: 640px) {
  .bank-card { grid-template-columns: 40px 1fr; }
  .bank-card .bank-actions {
    grid-column: 1 / -1;
    flex-direction: row;
    align-self: stretch;
  }
  .bank-card .bank-review,
  .bank-card .bank-cta { flex: 1; }
}

/* ─────────────────────────────────────────────────────────────
   Reduced motion
   ───────────────────────────────────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}